1. Field of the Invention
This invention relates to bags used for collecting debris that is collected by a vacuum cleaner and, more specifically, to reusable cloth bags which may be used to collect fine particulate matter.
2. Description of the Prior Art
Typical central vacuum cleaner systems and portable wet/dry vacuum cleaners have a large collection canister with an inlet near the top thereof. All of the rigid vacuum lines within a house or building having a single central vacuum cleaner system converge to this inlet. For a wet/dry vacuum cleaner, a flexible hose may generally be attached to this inlet. A top canister cover typically incorporates a motor and filter assembly. For a wet/dry vacuum cleaner, a foam filter may be used for suctioning up liquids, or a paper filter may be used when picking up dry debris. As central vacuum cleaner systems are generally designed to pick up only dry debris, the filter on those systems is typically either paper or cloth. Typically, filter surface area on both central vacuum cleaner systems and wet/dry vacuum cleaners is rather limited. When picking up coarse dry debris, the paper or cloth filters function quite well, as the average particle size is much greater than the pore size of the paper filter or cloth filter. However, when suctioning up fine particulate detrius, such as gypsum dust or fine sawdust, the filter will clog and become virtually worthlessxe2x80x94often within only seconds. As the pore size of the paper is very close to the size of the individual debris particles, each pore becomes irreversably clogged. Even back-flow air pressure may be incapable of unclogging the pores:of a paper filter. As each paper filter generally costs $10 to $20, the use of a central vacuum cleaner system or a wet/dry vacuum cleaner to pick up fine particulate debris can be very expensive and equally futile. Not only are the filters at risk under these conditions, but so are the electric motors. Because the motors of central vacuum cleaner systems and wet/dry vacuum cleaners rely on air flow to cool their powerful, high-amperage electric motors, a serious restriction or blockage of the airflow will result in overheating and concomitant destruction of the motor. As some central vacuum cleaner systems have multiple motors, a clogged filter can easily result a pair of damaged motors and hundreds of dollars in repair costs.
In accordance with the present invention, a new reusable and washable cloth vacuum cleaner filter bag is provided which solves the problems heretofore described. According to one aspect of the present invention, the new vacuum cleaner filter bag includes a first opening for receiving vacuumed debris, means for attaching the first opening to the tubular inlet of the wet/dry vacuum cleaner or central vacuum cleaner system, and a second opening, which is reversably sealable, for removing the vacuumed debris from the bag. A cloth filter bag, fabricated in accordance with the present invention, has been successfully used to suction up fine particulate debris, including gypsum dust and medium density fiberboard (MDF) dust. Particulate debris of these types will generally clog the filters of wet/dry vacuum cleaners and those of central vacuum cleaner systems very quickly. For a preferred embodiment of the new vacuum cleaner filter bag, the bag is fabricated from a tight weave, synthetic-fiber cloth having a warp of about 130 to 160 threads per inch and a weft of about 56 to 68 threads per inch. A synthetic cloth made of smooth filament fibers, such as nylon, rayon, polyester or polypropylene is deemed to be preferable to those made of fibers which are not smooth, as the cloth may be more easily cleaned. Rough fibers tend to trap dust particles, while smooth fibers tend to release them when agitated in a detergent solution. A variety of fastener types may be employed for the reversably sealable second opening. Hook and loop fasteners (of which the Velcro(copyright) brand fasteners are an example), compression-fit zip fasteners, and zipper fasteners and substitutes therefor are contemplated.
For one embodiment of the invention, the cloth filter bag is of generally rectangular shape having the first opening centered along the top edge thereof. The first opening incorporates a neck, by means of which the bag may be secured with an adjustable clamp to the inlet of the vacuum system. The entire lower edge of the bag incorporates the second opening, which is reversably sealable. The lower edge of the bag is constructed much like a polyethylene sandwich bag. That is to say that a cuff is made by folding back the cloth on one side of the opening and seaming the cuff at the lateral edges thereof. A first portion of the fastener is sewn or bonded to the face of the cuff, while the mating second portion of the fastener is sewn or bonded to the opposite opposing edge of the cloth on the other side of the bag. In order to seal the second opening of the bag, the cuff is turned inside out so that the face of the first fastener portion overlaps the second portion of the fastener, thereby allowing the two fastener portions to be sealably engaged. This arrangement is advantageous because the cuff can be returned to its original conformation after the second opening is unsealed, thereby permitting the bag to be emptied without the debris coming in contact with either fastener portions. This is particularly important where the fastener is of the hook and loop type. If such a fastener were in the path of the debris when the bag was emptied, the fastener could be easily fouled by debris particles. In addition, by folding the cuff over the opening when it is turned inside out, the opening is covered by filter cloth so that fastener is not directly exposed. If a hook and loop fastener were used to close the end of a bag having no cuff, the fastener material would be more likely to breathe, resulting in particulate debris being sucked through the fastener.